Carry save adders (CSAs) are widely used for multiply operations. In some conventional multiply implementations, either one partial product row for each bit in the multiplicand is produced, or Booth encoding schemes may be used to obtain partial products for each adjacent pair of bits in the multiplicand. The partial products are then added together to obtain a result. For example, multiplier architectures, which may be based on one of the Baugh-Wooley algorithms, Wallace trees, or Dadda multipliers, may add the partial products to obtain a result. To increase efficiencies, conventional CSA designs have often focused on reducing the number of partial product terms to be added. However, these designs limit the flexibility of CSAs. Because CSAs are large structures, which may sometimes take up a large portion of chip area, increasing the flexibility of CSA to perform a variety of operations is desirable.
Therefore, some disclosed embodiments present an efficient flexible CSA.